Spillers Records in Cardiff is the oldest record shop in the world. Every Saturday around 1986 and 1987, I and James Dean Bradfield, my bandmate in the Manic Street Preachers, would travel the 20 miles from Blackwood to go there and busk. The idea was to make enough money to buy a 7in single and a burger. The burgers came from Wimpy. The 7in singles came from indie bands no one really remembers now: the June Brides, McCarthy, Tallulah Gosh, Big Flame.

Music history holds that nothing much happened in British rock between the rise of the Smiths (early 1980s) and the rise of the Stone Roses (early 1990s), but something did. For want of a better name, it gets called C86, after a compilation tape the NME put out that year. It was iconoclastic and human, and so fiercely independent it was kind of beyond authenticity. Some people have called it the true birth of indie, in which case this year marks its 20th anniversary.

This music is ingrained in my skull and I can still hear it resonate today. I listen to the Arctic Monkeys and I think they sound like the Wedding Present. The last Franz Ferdinand single sounded like Up the Hill and Down the Slope, a single by the Loft, one of the first things released on Creation, the label that signed Oasis.

Twenty years on, if you listen to the actual C86 compilation tape, it doesn't sound like a scene at all - it's all over the place. Some of the bands, such as Big Flame, were abrasive. Some of them, like the Shop Assistants or the June Brides, were performing brilliant pop songs that teetered on the edge of falling apart. Then there was McCarthy, probably my favourite band of all time. They were quite fey musically, but their lyrics were so political and erudite: We Are All Bourgeois Now, The Procession of Popular Capitalism. Years later, the Manic Street Preachers covered a couple of McCarthy songs and I got a letter from the drummer saying: "From one failed commie to another, thanks for the royalties".

If there was any kind of coherence, it was the fact that the bands were so independent from the music industry and from the mainstream media. People were doing everything themselves: making their own records, doing the artwork, gluing the sleeves together, releasing them and sending them out, writing fanzines because the music press lost interest really quickly.

And they were all making up manifestos, no matter how ridiculous it seemed. When we first started, the Manics had a manifesto, too - no drugs, no sex before a gig, which was fairly easy to stick to because no one wanted to have sex with us - but in the C86 era, people were obsessed with things that seem odd now. Albums and CDs were held to be politically incorrect, for instance: bands would release only 7in singles.

Even at the time, being into C86 bands felt like being part of a secret society. The scene was snobbish and elitist - although in a really good way. If the bands had icons, they always seemed to be slightly under the radar: record sleeves wouldn't have a picture of Andy Warhol on them, but of some girl who had hung around the Factory for a couple of days in 1966. It forced you to think a bit - to discover things.

The bands were also very feminine and fragile, which was at odds with most rock music that had come before. Punk tended to be very macho. That wasn't an adjective you could attach to the Pastels, whose lead singer was a part-time librarian called Stephen who carried a satchel.

Most musical movements produce a stand-out musician, but there wasn't one with C86. Their records were badly produced, the singers were usually out of tune - but that was the appeal: it sounded human. Now music sounds sanitised. Bands like the Arctic Monkeys are great, but their records are so well-produced and slick.

C86 taught me that it was OK to make mistakes.

A couple of the bands went on to lasting success, including Primal Scream - who now seem really embarrassed about that era in their history. But most C86 bands had a lack of ambition in a really good way. There seemed no desire to make any money. Today's indie artists are well-groomed; in the C86 era, every band member had holes in their jumpers. It wasn't a punk thing, it was a poor thing. You also got the impression, looking at a C86 band, that a lot of these musicians were living at home with their parents. This was totally inspirational: here were people who were in a band and just like you.

The ICA in London is marking the 20th anniversary of the C86 era with a weekend of live shows, exhibitions and film screenings. I'm not sure if we need these gigs to remember it. The thing I loved about C86 was the romance and doomed elitism: it felt like nostalgia even as it was happening. It's telling that none of the original bands have actually reformed to play at the ICA, and that none of the individual records have been re-released. That somehow makes it more special, more precious. Some things are meant to be rare.

I still play my C86 records today and they never fail to lift me. Some of them are awful, some are shambolic, but I many of them are among the greatest records ever made.